Electro-acoustic transmission system for stereophonic sound phenomena



March 5, 1957 H. WINDISCH 2,784,253

ELECTRO-ACOUSTIC TRANSMISSION SYSTEM FOR STEREOPHONIC SOUND PHENOMENAFiled Nov. 7, 1951 'INVENTOR HEINZ WINDISCH Agent United States PatentELECTRO-ACOUSTIC TRANSMISSION SYSTEM FOR STEREOPHONIC SOUND PHENOMENAHeinz Windisch, Munich-Grosshadern, Germany, assignor to HartfordNational Bank and Trust Company, Hartford, Conn. as trustee ApplicationNovember 7, 1951, Serial No. 255,246 Claims priority, applicationGermany December 14, 1950 1 Claim. (Cl. 179-1) In radio transmissionengineering the magnetophone is used as a sound recording device. Inorder to permit the use of stereophony for radio purposes two soundtracks have been recorded on a single band for twochannel transmissionwith the use of a stereophonic device comprising a double-actionreproducing and recording head. Experiments made in thus recordingintelligence and music by way of two channels proved that themagnetophone is suitable more particularly for stereophonic records ofthis kind.

The present invention is based on the recognition that particularresults are obtainable by employing two-channel transmissionmagnetophones in electro-acoustic installations for the transmission ofchurch bell-ringing and the like in such manner that the microphonesused for recording the sound phenomena are arranged on both sides of theswinging bell(s) and at least substantially in the direction of motionthereof, two loudspeakers or loudspeaker sets for reproduction beingarranged on two opposite sides of the location of the hitherto usedbell(s).

The invention permits more particularly to replace the bell(s) atarbitrary locations by apparatus comprising a magnetophone, reproductionamplifiers and loudspeakers. It will be appreciated that a reproducinginstallation of this type is easily displaceable in contradistinction toheavy bells. In addition, the bell-ringing can be determined at will bya corresponding choice of the bell(s) used in recording and is easilyvariable by recording a difierent ringing on another band.

In order that the invention may be more clearly understood and readilycarried into effect, it will now be described more fully with referenceto the accompanying drawing, representing diagrammatically anelectro-acoustic transmitting installation according to the invention.

Fig. 1 shows the arrangement of the individual parts of the installationused in the recording bell-ringing. Fig. 2 showing the arrangement usedfor reproduction.

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As appears from Fig. 1 microphones M1 and M2 are arranged on both sidesof the swinging bell G and preferably in the direction of oscillation.In this arrangement now the microphone M1, now the microphone M2 willtake up the major part of the sound in accordance with the phase ofmotion of the swinging bell. The microphone amplifiers are designated V1and V2, the doubleaction magnetophone being denoted by M. Such amagnetophone comprises in a known manner double-action recording headsby which two sound tracks separated by a neutral zone are recordedsimultaneously. By providing corresponding double-action reproducingheads the recorded sound can be reproduced stereophonically throughamplifiers V3, V4 and loudspeakers L1, L2 (Fig. 2). The loudspeakers,which may alternatively be replaced by loudspeaker sets, are preferablyarranged at opposite sides of the tower T in a direction in which thehitherto used bell(s) oscillate.

Advantageously the loudspeaker sets may, for example, each comprisethree loudspeakers having a wide band.

According to the invention it is advisable to use a plurality ofdouble-action magnetophones if particular ringing combinations andcarillon playing are to be reproduced.

Fundamentally, two normal magnetophones may be used for the soundrecording of both channels. In practice, however, it is difficult tooperate both apparatus in step in an adequate manner for stereophony.

What I claim is:

A system for recreating the sound of a bell swinging in a predeterminedarcuate path comprising means for separately detecting the sound of saidbell at two spaced points on opposite sides of said bell substantiallyin the plane of said path, means for separately recording the sounddetected at each of said two points in separate channels of a soundcarrier, means for separately reproducing the sound recorded in saidchannels, and means for projecting the sound separately reproduced fromeach of said channels in opposite directions from the reproduction meansto thereby audibly create the effect of a swinging bell.

References Cited in the file of this patent UNITED STATES PATENTS KunizIan. 15, 1952

